Another option is to suspend the foreground process (ctrl-Z) then you can background it by typing bg, which will resume running and put it in the background.
# sleep 10 ^Z [1]+ Stopped sleep 10 m # bg [1]+ sleep 10 & #
Another option is to suspend the foreground process (ctrl-Z) then you can background it by typing bg, which will resume running and put it in the background.
# sleep 10 ^Z [1]+ Stopped sleep 10 m # bg [1]+ sleep 10 & #